The present invention relates to polymerase chain reaction (PCR) instruments, particularly to a PCR thermocycler, and more particularly to a sleeve-type silicon thermocycler having improved thermal performance.
Most PCR instruments are large bench top systems that can do large numbers of samples, are relatively slow, and use large amounts of electrical power. Recently, efforts have been directed to the development of miniature PCR chambers which utilize so-called sleeve-type silicon reaction chambers involving doped polysilicon for heating and bulk silicon for convective cooling. The sleeve-type reaction chambers are exemplified by U.S. Pat. No. 5,589,136 issued Dec. 31, 1996, as well as copending U.S. application Ser. No. 08/489,819, filed Jun. 13, 1995, entitled xe2x80x9cDiode Laser Heated Micro-Reaction Chamber With Sample Detection Means,xe2x80x9d and U.S. application Ser. No. 08/763,465, filed Dec. 11, 1996, entitled xe2x80x9cMicrofabricated Sleeve Devices for Chemical Reactions,xe2x80x9d each assigned to the same assignee.
The present invention provides an improved or advanced sleeve-type silicon PCR chamber by reducing the thermal mass and increasing the surface area of the sleeve for cooling, thereby increasing the speed and the efficiency thereof. This is carried out by etching grooves along the faces of the sleeve and etching a series of grooves on the interior surfaces that connect with the face grooves. The grooves are anisotropically etched in the silicon wafers simultaneously with the formation of the chamber features of the sleeve, such that the inside grooves are etched with the chamber, but the outside grooves are etched separately.
It is an object of the present invention to provide an improved PCR chamber.
A further object of the invention is to provide a silicon-based sleeve type chemical reactor or thermocycler with improved thermal performance.
A further object of the invention is to modify existing sleeve-type reaction chambers to reduce the thermal mass and increase the surface area for enhanced cooling.
Another object of the invention is to provide an improved microfabricated chemical reactor having a sleeve reaction chamber with a slot therein for introducing reaction fluids, wherein the sleeve reaction chamber is provided with an arrangement of grooves to increase the surface area for more efficient cooling.
Another object of the invention is to provide an advanced silicon PCR chamber or thermocycler having grooves therein to reduce the thermal mass and increase the cooling surface area.
Another object of the invention is to provide an advanced silicon PCR chamber having improved thermal performance resulting from grooves formed in the faces of the device forming the chamber and a series of interior grooves connected to the face grooves for increasing the surface area for cooling.
Other objects and advantages of the present invention will become apparent from the following description and accompanying drawings. Basically, the present invention is a PCR thermocycler with improved thermal performance. The invention involves a modification of the so-called sleeve or sleeve-type reaction chambers, such as exemplified in the above-referenced patent and copending applications. The improved thermal performance of the silicon PCR chamber of the present invention is accomplished by modification of the sleeve to include a groove arrangement in the external faces of the sleeve and on the interior surfaces to provide increased surface area for enhanced cooling. These modifications, accomplished by anisotropically etching simultaneously with the formation of the chamber, increase the speed and efficiency of the silicon sleeve PCR chamber.